Book Image

Learning YARN

Book Image

Learning YARN

Overview of this book

Today enterprises generate huge volumes of data. In order to provide effective services and to make smarter and more intelligent decisions from these huge volumes of data, enterprises use big-data analytics. In recent years, Hadoop has been used for massive data storage and efficient distributed processing of data. The Yet Another Resource Negotiator (YARN) framework solves the design problems related to resource management faced by the Hadoop 1.x framework by providing a more scalable, efficient, flexible, and highly available resource management framework for distributed data processing. This book starts with an overview of the YARN features and explains how YARN provides a business solution for growing big data needs. You will learn to provision and manage single, as well as multi-node, Hadoop-YARN clusters in the easiest way. You will walk through the YARN administration, life cycle management, application execution, REST APIs, schedulers, security framework and so on. You will gain insights about the YARN components and features such as ResourceManager, NodeManager, ApplicationMaster, Container, Timeline Server, High Availability, Resource Localisation and so on. The book explains Hadoop-YARN commands and the configurations of components and explores topics such as High Availability, Resource Localization and Log aggregation. You will then be ready to develop your own ApplicationMaster and execute it over a Hadoop-YARN cluster. Towards the end of the book, you will learn about the security architecture and integration of YARN with big data technologies like Spark and Storm. This book promises conceptual as well as practical knowledge of resource management using YARN.
Table of Contents (20 chapters)
Learning YARN
Credits
About the Authors
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Introduction to YARN REST services


All YARN daemons expose a set of URIs as REST APIs to fetch cluster information. The format for a URI representing a REST API is as follows:

http://{http address of service}/ws/{version}/{resourcepath}

It consists of the following three placeholders:

  • http address of service: This is a set of the host name (or IP address) and HTTP port for a YARN service or a DNS mapping to host and port, if hosted publically. For example, the HTTP address of a REST API for ResourceManager with host name master and HTTP port 8088 will be master:8088.

  • version: This is the latest version number for the APIs defined by YARN services. The current version of YARN services is v1.

  • resourcepath: This path is uniquely resolved to a resource at the server. For example, the value of a resource path defined to fetch cluster metrics is cluster/metrics.

Hence, a sample URI for the ResourceManager service to fetch cluster metrics will be:

http://master:8088/ws/v1/cluster/metrics.

HTTP request...